Optical reflection methods and apparatus for aligning communication system components

Abstract

Measuring and setting techniques for relative component orientations and separations is accomplished by projecting a coherent light beam into one end of a gap formed between facing surfaces of adjacent components. This light beam projection causes a corresponding light ray pattern to be projected out of an opposite end of the gap. The arrangement of light rays in the resulting pattern is indicative of the relative positions of, and distance between, the facing surfaces. Such a projected pattern is used for determining the relative positions between adjacent components, alone, or as feedback for adjusting such component positions to achieve a desired orientation and/or separation distance between the components.

The invention claimed is: 
     
       1. A method of adjusting positions of adjacent components relative to one another comprising the steps of: directing a coherent light beam into one end of a gap formed by facing surfaces of said components, wherein said directed light beam is reflected from the facing surfaces of said components and causes a projection of a light ray pattern out of an opposite end of said gap;   detecting characteristics of said projected light ray pattern; and   adjusting the position of one of said components relative to the other of said components based on said detected pattern characteristics to achieve a desired relative orientation and/or separation between said components.   
     
     
       2. The method of claim 1 wherein a length of said gap in a direction of said light beam is at least five times longer than a separation distance between said facing component surfaces. 
     
     
       3. The method of claim 1 wherein said step of detecting projected light ray pattern characteristics includes the steps of identifying positions of illuminated pattern regions due to reflection. 
     
     
       4. The method of claim 1 wherein said step of detecting projected light ray pattern characteristics includes the steps of identifying positions of illuminated pattern regions due to diffraction. 
     
     
       5. The method of claim 1 further comprising the step of determining relative component positions based on said detected pattern characteristics, wherein said step of adjusting the position of one of said components is based on said determined relative positions. 
     
     
       6. The method of claim 5 wherein said step of determining relative component positions includes the step of determining a separation distance between said components based on a detected period of light intensity for illuminated pattern regions due to diffraction. 
     
     
       7. The method of claim 1 further comprising the step of coating at least one of said surfaces with a substantially reflective material. 
     
     
       8. The method of claim 7 further comprising the step of removing said coating after the desired relative orientation has been achieved. 
     
     
       9. The method of claim 1 wherein at least one of said components is an integrated optical device and said method farther comprises the step of coupling the component to said device after the desired relative orientation and/or separation has been achieved. 
     
     
       10. A method of determining relative positions of facing surfaces of adjacent components comprising the steps of: directing a coherent light beam into one end of a gap formed by said facing surfaces, wherein light reflects off of the facing surfaces of said components to project a light ray pattern out of an opposite end of said gap;   detecting characteristics of said projected light ray pattern; and   determining said relative positions based on said detected pattern characteristics.   
     
     
       11. The method of claim 10 wherein a length of said gap in a direction of said light beam is at least five times longer than a separation distance between said facing component surfaces. 
     
     
       12. The method of claim 10 wherein said step of detecting projected light ray pattern characteristics includes the steps of identifying positions of illuminated pattern regions due to reflection. 
     
     
       13. The method of claim 10 wherein said step of detecting projected light ray pattern characteristics includes the steps of identifying positions of illuminated pattern regions due to diffraction. 
     
     
       14. The method of claim 13 wherein said step of determining said relative positions includes the step of determining a separation distance between said components surfaces based on a detected period of light intensity of said projected light ray pattern portions due to diffraction. 
     
     
       15. The method of claim 10 further comprising the step of adjusting the position of one of said components relative to the other of said components based on said determined relative positions to achieve a desired relative orientation and/or separation. 
     
     
       16. The method of claim 10 further comprising the step of coating at least one of said surfaces with a substantially reflective material. 
     
     
       17. The method of claim 16 further comprising the step of removing said coating after said alignment has been determined. 
     
     
       18. An apparatus for setting desired relative positions of first and second components relative to one another comprising: a controllable positioner, said positioner for retaining said components and for adjusting a relative position of said first component relative to said second component;   a coherent light source, said light source for directing a coherent light beam into a gap formed by facing surfaces of said components;   a light ray pattern detector, said detector for detecting a pattern of light rays projected from said gap by reflection of light from the facing surfaces of said components; and   a controller coupled to said positioner and said light ray pattern detector, said controller for determining characteristics of a light ray pattern detected by said detector and controlling said positioner to adjust said positions based on said determined characteristics.   
     
     
       19. An apparatus for determining relative positions of first and second adjacent components with respect to one another comprising: a coherent light source, said light source for directing a coherent light beam into a gap formed by facing substantially reflective surfaces of said components;   a light ray pattern detector, said detector for detecting a pattern of light rays projected from said gap by reflection of light from the facing surfaces of said components; and   a processor coupled to said light ray pattern detector, said processor for determining characteristics of a light ray pattern detected by said detector and determining said relative positions based on said detected pattern characteristics.